Error loading NEXRAD file into bioRad - file not found

I am trying to read a NEXRAD polar volume using bioRad in R Studio, but I get an error saying the file does not exist when it does in fact exist in the proper directory. Any thoughts on how to solve this?

input code: read_pvolfile("/directory/FOP120200101_000209_V06")

result:

Error: input file 'FOP120200101_000209_V06' does not exist.
Error in nexrad_to_odim_tempfile(file, verbose = verbose, mount = mount) : 
  Failed to run nexrad_to_odim (rsl2odim) in Docker container.```